From 317b95be317ea038ad9fa398fc0c0c456b53495d Mon Sep 17 00:00:00 2001
From: Wolfgang Witt <Wolfgang.Witt@campus.lmu.de>
Date: Sat, 6 Feb 2021 15:42:24 +0100
Subject: [PATCH] fix: check if number of relevant user is >0 to prevent crash

---
 src/Handler/Utils/Exam.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Handler/Utils/Exam.hs b/src/Handler/Utils/Exam.hs
index 872d63c35..cfb4124c2 100644
--- a/src/Handler/Utils/Exam.hs
+++ b/src/Handler/Utils/Exam.hs
@@ -269,7 +269,7 @@ examAutoOccurrence :: forall seed.
 examAutoOccurrence (hash -> seed) rule ExamAutoOccurrenceConfig{..} occurrences users
   | sum occurrences' < usersCount
     || sum occurrences' <= 0
-    || Map.null users
+    || Map.null users'
   = nullResult
   | otherwise
   = case rule of